Why did we wait so long for the cotton gin?

November 25, 2017

Eli Whitney’s cotton gin, invented in 1793, is rightfully one of the most famous inventions of the Industrial Revolution. It separates the lint of the cotton plant, which thread and ultimately cloth is made of, from the sticky seeds—a process that, done by hand, is the definition of “tedious”.

As told in Stephen Yafa’s history of cotton, Whitney invented the device after plantation owner Katy Greene invited him to sit in on a meeting of Southern cotton farmers:

Their common problem, he quickly discovered, was that they had no way to remove the stubborn green seeds of upland cotton from the fibers except by hand, and so they planted it only sparingly. Each five-hundred-pound bale of upland took as many as sixteen months of a single slave’s dedicated work to separate. The cost of feeding and clothing the slave for that period cut deeply into profits. The farmers’ other crops—rice, tobacco, corn, and indigo—were barely providing a livelihood. Tobacco exhausted the land and could not be trusted to provide steady future income. The British were expanding their indigo plantations in Bengal, weakening the market for American dyestuff. Wetland rice required special conditions for cultivation, insuring that it would never be a widespread crop. …

Green-seeded cotton grew like kudzu in this climate; there was a fortune waiting to be made and no way to make it. What to do? “Gentlemen, apply to my young friend, Mr. Whitney,” Katy told the assembled group of frustrated farmers. “He can fix anything!”

Ten days later Whitney came back with a working model of his cotton gin—crude, but essentially governed by mechanical design principles that are still in operation today. No engineers since have reinvented a better gin; they’ve simply built better versions of Whitney’s original. Legend has it that Whitney’s inspiration came as he was roaming the plantation grounds pondering how to solve the problem and paused to watch a cat hunt down a chicken. At the last moment the chicken fled and the cat’s lunging paw came away with only a few feathers. Why then try to separate the seeds of upland cotton from its fibers? Why not instead build a device to separate the fibers from the seeds? Small difference, huge implications. If Whitney’s machine could allow the fibers to be pulled away while creating a barrier that held back the seeds, the claws could exert enough force to yank the fibers free.

That elegantly uncomplicated premise led Whitney to build an apparatus that duplicated the motions of the slaves who cleaned cotton manually. He fashioned a mesh sieve or hopper with narrow slits in it running lengthwise to do the work of the hand holding the seed. On the surface of a drum rotating around the hopper he duplicated fingers pulling off the lint by attaching wire claws that protruded through the slits; these hooks grabbed the lint and wrenched it away from the seeds, which were held in check by the tight mesh. A cylindrical brush swept off the freed lint. This hand-cranked contraption, the cotton gin, was, in Whitney’s words, “an absurdly simple contrivance”—and unfortunately for Whitney, he was right: it was all too easy to copy.

So:

The need for a better way to remove seeds from cotton was well-known, and it was clear that a solution would have huge economic value.

The solution was not obvious—it did require a flash of mechanical insight—but it did not take Whitney long to come up with it; only ten days (!) after encountering the problem. And note that Whitney had not been thinking about the problem for a long time (he had come to the South to be a tutor, and only took on the problem when that job fell through); so this is not a case of “prepared mind”, except in the very general sense that Whitney was an experienced mechanical engineer.

The solution was simple: so simple, in fact, that Whitney had a hard time receiving patent royalties for his invention, because any plantation owner could rig one up in his shed.

Unlike the steam engine, the invention did not require any special principles of physics, just simple mechanical ingenuity. Nor did it require any special or newly invented materials, only wood and metal.

Given the above I see no reason why the cotton gin couldn’t have been invented a century or more earlier than it was. Given the economic need, there was a strong incentive for its invention. So why did it wait so long?

The patent on the cotton gin, number 72X, was one of the earliest in America, filed only a few years after the first Patent Act. So one might be tempted to treat this as a case of patent law unleashing the creative force of entrepreneurial inventors. Certainly Whitney sought to make money from his invention (even if he was largely unsuccessful), and Greene, who sponsored his work, must have had this in mind as well. But suppose the Patent Act hadn’t been passed yet in 1793. Would Greene not have encourage Whitney to work on this problem that was so important to Southern plantation owners? Would Whitney not have bothered to solve it?

My personal, as-yet-unproven hunch is that cultural factors were significant here. This was the very dawn of the Industrial Revolution in America. People had not yet learned to expect mechanical inventions to revolutionize every aspect of life. They were used to the status quo and did not yet have “the idea of progress”, at least not in the industrial sense.